Centrifugal pump



Auge 14, 1945 c. E. wuENscH 2,382,839

CENTRIFUGAL PUMP Filed June 5, 1944 2 Shets-Sheet fio la 67 sa' v 9 a 2f ff@ l 6 26 /5 *zo a9 38 B l\l`l7 45 /NVEA/TUL CHARLEj ERB WUENSCH 5y ALM.,

Aug. 14, 1945.

.'lllllll 'INV- Y, I `i l C. E. WU ENSCH GENTRIFUGAL PUMP Filed June 5, 1944 2 SheetsdSheet 2 IN V EN TOR.

CHALEj ERB WUENSCH grrr.

Patented Aug. v14, 1945 UNITED STATES PATENT OFFICE CENTRIFUGAL PUMP Charles Erb Wuensch, Saratoga, Calif. Application June 5, 1944, Serial No. 538,793

3 claims. (ci. 10s-112i) 'I'he present invention relates to centrifugal pumps, and particularly to centrifugal pumps which are principally employed in pumping sand, grit and other abrasive material both by pressure feed and by suction.

The conventional centrifugal pump engaged in the pumping of grit and other forms of abrasive and granular material rapidly decreases in pumping eiilciency during operation due to the constant wear of the abrasive particles on the sev- -maintenance and the stopping of the pumping operation until repairs and replacements can be The invention resides in the combination and construction of parts illustrated in the accompanying two sheets of drawings which show the device in a preferred embodiment. It is understood that the drawings are illustrativesonly and that the invention is capable of modification and structed in accordance with this invention, taken made. The frequency of such shutdowns `either brings about a substantial investment in an ab` normal amount of replacement pumps and parts or an inordinate waste of time due to the frequency of the stops. In the pumps heretofore known and used it is the unfailing experience that when wear once begins it becomes increasingly greater andmore rapid with a consequent increase of ineillciency in the operation until complete shutdown is required.

Among the objects of the present invention is to minimize the wear in centrifugal pumps caused by pumping abrasive and other substances in suspension.

It is also an object to provide a centrifugal pumping device where the minimum initial clearance between the impeller and the enclosing casing can be maintained and regulated throughout the entire life of the pump.

Another object is to reduce the rst cost and maintenance of centrifugal pumps and increase their emciency under the abusive condition of their ,normal operation.

Another object is to provide a centrifugal pump which because of the regulated clearance between the impeller and its enclosing casing,` delivers a larger volume than any standard centrifugal pump of equal size running under the same or similar conditions. i

Another object of the present invention' is to protect the pump mechanism from injury by pebbles and other large objects travelingin the ow of the material being pumped.

Still another object of the invention is to provide a pump mechanism which will resist abrasion to a greater 'extent than any priori pump and in which replacements take less time to install and are much less costly.

Such other objects as may become apparent as yand contemplated herein.

on the line I-I of Figure 2,

Figure 2 is a side elevation of the same, partially broken away to disclose the underlying structure.

Referring now more in detail to the drawings, the structure illustrated, referring first to Figure '-l', comprises the base I, supporting the cylindrical case 2 having the tangential outlet 3. The side plates 4 and 5 are bolted to the case, as at B, 1 tocomplete the enclosing casing. The plate 4 has the axial suction or feed inlet 8 with the annular flange 9 bolted to the side plate 4 at I0. The case 2 has a bowl liner I-I bolted thereto at intervals, as at i2. The bowl liner Il is preferably of rubber composition or some other elastic or resilient material. The inner periphery of this liner is preferably arcuate'in cross section, as indicated at I3. n

The base l has a pair ofrspaced pillars Il supporting bea g housings I5, only one pillar being shown in t e drawings. The-driven shaft i6' is .mounted with suitable bearings in the housings l5, and the driving pulley (not shown), is keyed to shaft I6 between the two bearings l5. It is to be understood `that any suitable means for driving shaft i6 may be used.

The impeller hub Il is fixed to the end of the shaft It within the casing. Impeller blades I8 are attached to the hub I1 in any suitable manner calculated to keep'them in place during operation and at the same time permit them to be removed readily in ease of repair or replacement. While the blades are held rigidly in position they are in fact flexible so as to be free to react both to centrifugall force and to yield to permit larger particles to .pass through without stopping'the pumping action. 'I'he blades I8 are shown to extend radially from the hub I'l to proximity with the elastic or resilient bowl liner Il but they may also be placed tangentially. It is to be understood that their constructionl and the degree of flexibility will vary in accordance withthe nature of the material to be pumped although the structure described.herein is capable of handling all conditions normally encountered.

The impeller blades are preferably constructed in accordance with the disclosure cf a pending application filed June 5, 1944, and serially num-l bered 538,794. For general all around work good results have been obtained from an impeller having Aa central internal support I9 (see Figure 2) around which is molded or shaped the impeller blades designated I8. Tough rubber or any other suitable resilient material may be molded `around the central support to form the blades I8. The central support I9 maybe formed with atransverse head 20 for keying and maintaining the same in the hub I1. In such event the hub I1 will have suitable slots foraccepting the keys 20. It may also be formed tapering to the outer end as shown in Figure 2 which will provide graduated flexibility. Beyond the end of the reinforcing blades I 8 yield more readily to the flexing forceV of rotationsee dotted line position-neutralizing to some extent the centrifugal force acting through the blades. The outer ends of the blades may be weighted in any suitable manner as at I9a. The purpose of weighting the outer ends is to give rigidity to the outer ends of the blades and also to stretch the blades slightly solas to minimize any tendency through centrifugal act'on to become larger in cross sectional diameter or area at the point of maximum flexure. It may be desirable to place holes 2| through the central support I9 in order to keyithe molding composition forming the resilient blades I8, through the central support I9.

The impeller blades I8 operate between two lateral resilient or flexible diaphragms 24 and 25 alike in contour and section, each having axial tubular necks 26 and 21, with lateral outwardly extending flanges 28 and 29 thereon, and peripheral collars 26a and 21a with outwardly extending flanges 30 and 3| respectively. The flange 28 is interposed between the flange 8 of the feed inlet and the side plate 4 and also ange 30 is interposed between side plate 4 and the cylindrical cover plate 2. In each instance the diaphragm iianges act as a gasket between the two holding members. On the opposite slide the flange 29 is held between the side plate and the fiat packing ring 32 which is bolted tothis place. The peripheral 'flange 3i acts as a gasket between the side plate Sand the cylindrical case 2 in a similar manner as above described. These resilient lateral diaphragms 24 and 25 thus completely seal the casing-joints against leakage and excessive wear and together with the liner I I define a chamber in which the impeller operates. The diaphragms 24 and 25 form the side walls of the pumping chamber providing sc ant clearance for the blades I8 and the inner liner II provides the cylindrical wall just beyond the ends of the blades.

The spaces between the diaphragms 24 and 25 and thev respective side'plates 4 and 5 form expansion chambers 33 and 34 which are interconnected by the bypass pipe 35 for equalizing the pressures in the two chambers. A hand pump 36, or any other suitableA device or connection, is connected to this pipe and supplies either air or hydraulic pressure to expand the chambers 33 and 34 inwardly toward the impeller blades to regulate the clearance, the pressure being indicated by the gauge 38. The diaphragms are expanded until the gauges show but minor fluctuations. A stop or check valve 3'1 is provided in the line and may if necessary be used to release the pressure inthe chambers 33 and 34. Instead rotating seal includes a threaded sleeve 38 having.

an inner flange 39, which is keyed to the shaft I8 adjacent the hub I1. Resilient annular sealing rings 40 and 4I have lips bearing against the opposite sides of the stationary ring 32. The locking rings 42 and 43 are threaded on the sleeve 38 and'bear against the inner sides of the sealing rings 40 and 4I respectively. The stiff expansive spring 41 encircles the sleeve 38 between the locking rings 42 and 43 to frictionally prevent them from backing away from the sealing rings 40 and 4I respectively. The external running nut 45 is threaded on the' outer end of the sleeve and fixed to the shaft I8 by the set screw 48. This form of packing is highly efllcient and operates 'with the minimumof friction against the ring 32. The rotation of the ring 40 tends to throw gritty particles away from the contact with the sealing ring. The space between the rings 43 and 4I is kept filled with grease or water by the compression drip cup 48,

This invention operates substantially as follows: the pumped material entering the inlet 8, is driven outward by the impeller blades I3 against the liner II of the case and between the diaphragms 24 and 25 until the volume builds up end then itis forced through the outlet 3. The diaphragms 24 and 25 are deflected inwardly into approximate or actual contact with the sides of the impeller blades I8 by the pressure within the chambers 33 and 34 by means of the hand pump 35. Any degree of clearance may be maintained by adjusting the pressure in chambers 33 and 34. The pressure output from the casing can be increased by increasing the pressure within the chambers 33 and 34 until the diaphragms 24 and 25 bear lightly against the sides of the impeller blades I8, preventing backslip in the centrifugal output. 'I'hese are features particularly valuable in centrifugal pumping. y

In pumping sand, gravel and waste waters there are occasional obstructive bodies such as rocks and ilotsam that would injure and stop the conventional pumps having rigid clearances. In the present invention the diaphragms 24 and 25 and the flexible impeller blades I8 yield clearance and permit the obstructive object to pass.

A useful feature of the present device is the ease with which repairs and replacements can be made. I'he diaphragms 24 and 25 may be removed, as well as the cylindrical liner II, by removing the side plate 4, loosening the opposite side plate 5, and removing the individual impeller blades I8.

It is to be understood that in maintaining the pressure against the diaphragms 24 and 25 any suitable automatic means may be substituted for the hand pump. The automatic means may be set to maintain any predetermined pressure or series of pressures.

I claim:

1. A centrifugal pump comprising'in combination a case having side plates forming an enclosing casing with inlet and outlet openings, an impeller in said casing between said openings, resilient diaphragms interposed between said covers aseassa and forming pressure chambers on the opposite sides of said impeller, and means for varying the pressure in said chambers to deflect said diaphragms relative to said impeller.

2. A centrifugal pump comprising in combination, a case having a resilient interliner and opposed cover plates forming an enclosing casing with inlet and outlet openings, an impeller in said casing between said openings, flexible diaphragme having their peripheries interposed between said case and covers respectively and forming pressure chambers on the opposite sides of said impelier, means for interconnecting said pressure chambers, and means for varying the pressure in i said chambers for deecting said diaphragms relative to said impeiler.

an outlet opening including side plates ixedl to the opposite sides of said case and a resilient peripheral inner liner therebetween, an impeller between said plates and having a shaft projecting through one of said side plates, flexible dia.- phragms having peripheral flanges for holding said diaphragms in place within the case and acting as gaskets therefor, interconnecting pressure chambers between said diaphragms and said side plates, a fiat packing ring encircling said shaft and xed to said casing, a pairof sealing rings xed on said shaft and bearing against the opposite sides of said packing ring, and means for introducing pressure into the pressure chambers between said side plates and said diaphragms, and means for automatically maintaining the same.

CHARLES ERB WUENSCH. 

